Asymmetric injection for better wafer uniformity

ABSTRACT

A gas injector for processing a substrate includes a body having an inlet connectable to a gas source that is configured to provide a gas flow in a first direction into the inlet when processing a substrate on a substrate support disposed within a processing volume of a processing chamber, and an a gas injection channel formed in the body. The gas injection channel is in fluid communication with the inlet and configured to deliver the gas flow to an inlet of the processing chamber. The gas injection channel has a first interior surface and a second interior surface that are parallel to a second direction and a third direction. The second and third directions do not intersect a center of the substrate, and are at an angle to the first direction towards a first edge of the substrate support.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit to U.S. provisional applicationsNos. 62/798,474, filed Jan. 30, 2019, and 62/897,900, filed Sep. 9,2019, each of which is incorporated by reference herein.

BACKGROUND Field

The present disclosure relates generally to a semiconductor processingapparatus and processing method, more specifically, to a reactor with animproved gas flow distribution.

Description of the Related Art

In fabrication of memory gate oxides, liner oxides, sacrificial oxides,sidewall oxides, flash tunnel oxides, oxide-nitride-oxide (ONO) stacks,or the like in integrated circuits and micro-devices, semiconductorsubstrates may be processed by rapid thermal oxidation. In this process,an oxide layer may be formed on a substrate by exposing the substrate tooxygen and hydrogen based reactant gas while heating the substrate witha radiant heat source to produce oxygen and hydrogen radicals. Oxygenradicals strike the surface of the substrate to form an oxide layer, forexample a silicon dioxide layer on a silicon substrate.

In existing processing chambers used for rapid thermal oxidation, gasinjection mechanisms distribute reactant gas non-uniformly over thesubstrate, resulting in poor thickness uniformity in an oxide layer onthe substrate. Conventionally, a rotatable substrate support rotates asubstrate while a reactant gas is introduced straight towards the centerof the substrate. The reactant gas is distributed more at the center ofthe substrate and less near edges of the substrate, and thus thicknessof an oxide layer grown near the edges of the substrate is less than ator near the center of the substrate.

Therefore, there is a need for an improved injection mechanism thatdistributes reactant gas more uniformly over the substrate.

SUMMARY

Implementations of the present disclosure provide apparatus forimproving gas distribution during thermal processing. One implementationof the present disclosure provides an apparatus for thermal processing asubstrate. The apparatus includes a body, an angled projection, and agas injection channel. The gas injection channel has a first half-angleand a second half-angle. The first half-angle is different from thesecond half-angle.

Another implementation of the present disclosure provides an apparatusfor processing a substrate comprising a chamber body defining aprocessing volume and a substrate support disposed in the processingvolume. The substrate support has a substrate supporting surface. Theapparatus also includes a gas source projection coupled to an inlet ofthe chamber body, an exhaust assembly coupled to an outlet of thechamber body, and a side gas assembly coupled to a sidewall of thechamber body. The side gas assembly includes a gas injection channel.The gas injection inlet includes a first half-angle and a secondhalf-angle. The first half-angle is different from the secondhalf-angle.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toimplementations, some of which are illustrated in the appended drawings.It is to be noted, however, that the appended drawings illustrate onlytypical implementations of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective implementations.

FIG. 1A is a schematic cross-sectional view of a processing chamberaccording to one embodiment.

FIG. 1B is a schematic cross-sectional top view of a processing chamberaccording to one embodiment.

FIGS. 2A and 2B show numerical simulations of oxygen radicalconcentration over a substrate according to embodiments.

FIG. 3A is a schematic cross-sectional top view of a gas injectoraccording to one embodiment.

FIGS. 3B and 3C are three-dimensional schematic views of a gas injectoraccording to one embodiment.

FIG. 4 is a schematic cross-sectional top view of a gas injectoraccording to one embodiment.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in someembodiments may be beneficially utilized on other implementationswithout specific recitation.

DETAILED DESCRIPTION

Embodiments described herein generally related to a semiconductorprocessing apparatus and processing method, and, more specifically, to areactor with an improved gas flow distribution. Embodiments of thedisclosure provide an asymmetric gas injector that includes a gasinjection channel that is configured to inject a gas towards an edge ofa substrate disposed in a process chamber, thereby increasing a reactionwith the gas at or near the edge of the substrate. Embodiments of thedisclosure further provide a side pump that is configured to redirectthe gas towards an opposing edge of the substrate, thereby increasing areaction across the substrate surface and the opposing edge of thesubstrate. Thus, a layer formed over the substrate by the injected gasis uniform across the substrate surface.

In the following description, an orthogonal coordinate system includingan X axis, a Y axis, and a Z axis is used. The directions represented bythe arrows in the drawing are assumed to be positive directions forconvenience.

FIG. 1A is a schematic cross-sectional view of a processing chamber 100according to one embodiment. The processing chamber 100 generallyincludes a lamp assembly 110, a chamber body 130 defining a processingvolume 139. A substrate support 138 disposed in the processing volume139 in a X-Y plane. The processing chamber 100 provides a controlledthermal cycle that heats a substrate 101 to perform one or more thermalprocesses on the substrate 101, such as thermal annealing, thermalcleaning, thermal chemical vapor deposition, thermal oxidation andthermal nitridation.

The lamp assembly 110 may be positioned relatively above the substratesupport 138 in the Z direction to supply heat to the processing volume139 via a quartz window 114. The quartz window 114 is disposed betweenthe substrate 101 and the lamp assembly 110 in the Z direction. The lampassembly 110 may additionally or alternatively be disposed below thesubstrate support 138 in the Z direction in some embodiments. The lampassembly 110 houses a heating source 108, such as tungsten-halogen lampsfor providing an infrared heating means to a substrate 101 disposed onthe substrate support 138. The tungsten-halogen lamps may be disposed ina hexagonal arrangement. The heating source 108 may be controlled by acontroller 107 to achieve a uniform or tailored heating profile to thesubstrate 101. In some embodiments, the heating source 108 can rapidlyheat the substrate 101 at a rate of from about 5° C./s to about 280°C./s.

The substrate 101 may be heated to a temperature ranging from about 450°C. to about 1100° C. The heating source 108 may provide temperaturetuning of the substrate 101 at certain locations while not affectingtemperatures at other locations. A slit valve 137 may be disposed on abase ring 140 for a robot to transfer the substrate 101 into and out ofthe processing volume 139. The substrate 101 may be placed on thesubstrate support 138. The substrate support 138 may move vertically inthe Z direction and rotate in the X-Y plane about a central axis 123. Agas inlet (also referred to as a chamber gas inlet) 131 may be disposedover the base ring 140 in the Z direction and connected to a gas source152.

FIG. 1B is a schematic cross-sectional top view of the processingchamber 100. As shown in FIG. 1B, the gas inlet 131 and a gas outlet(also referred to as a chamber gas outlet) 134 are disposed on oppositesides of the processing volume 139 in the X direction. The gas inlet 131and the gas outlet 134 may have a linear or azimuthal width whichapproximately equals a diameter of the substrate support 138.

Referring to both FIGS. 1A and 1B, the gas outlet 134, formed on anopposite side of the base ring 140 from the gas inlet 131 in the Xdirection, is an exhaust assembly 124 which is in fluid communicationwith first and second main exhaust pumps 160, 136 on the sidewalls ofthe chamber body 130 that have openings 160A and 136A, respectively,that are opposite to each other in the Y direction. The exhaust assembly124 defines an exhaust volume 125. The exhaust volume 125 is in fluidcommunication with the processing volume 139 via the gas outlet 134. Insome embodiments, the gas outlet 134 may include a perforated plate 135that includes a series of thru holes that are configured to restrict gasflow therethrough and thus provide a uniform draw of gases from theprocessing volume 139 (i.e., uniform in the Y-Z plane). However, inother embodiments, the perforated plate 135 is either not used in theprocessing chamber 100 or is configured to provide a minimal restrictionto the flow of gas from the processing volume 139 to the exhaust volume125, and thus allows the position of the openings 160A and 136A toaffect the flow pattern within the processing volume 139 and the exhaustvolume 125. In one example, as shown in FIG. 1B, the configuration ofthe openings 160A and 136A is such that the flow pattern in the exhaustvolume 125 and later portion of the processing volume 139 is higher atthe left extent of the processing volume 139 (i.e., near a second edge302) due to the position of opening 136A and higher at the right extentof the processing volume 139 (i.e., near a first edge 304) due to theposition of opening 160A, and thus has a proportionally smaller flow inthe middle of the exhaust volume 125 and later portion of the processingvolume 139. In another example, the second main exhaust pump 136 isturned off and the first main exhaust pump 160 is used to pump gasesfrom the processing volume 139 and exhaust volume 125 via the opening160A such that the flow pattern in the exhaust volume 125 and laterportion of the processing volume 139 is higher at the right extent ofthe processing chamber due to the position of opening 160A, and thus hasan increasing gradient in flow from the left side to the right side ofthe exhaust volume 125 and later portion of the processing volume 139(e.g., increasing gradient is in the −Y-direction). In yet anotherexample, the first main exhaust pump 160 is turned off and the secondmain exhaust pump 136 is used to pump gases from the processing volume139 and exhaust volume 125 via the opening 136A such that the flowpattern in the exhaust volume 125 and later portion of the processingvolume 139 is higher at the left extent of the processing chamber due tothe position of opening 136A, and thus has an increasing gradient inflow from the right side to the left side of the exhaust volume 125 andlater portion of the processing volume 139 (e.g., increasing gradient isin the +Y-direction).

In some embodiments, a side port 122 may be formed within the base ring140 on a sidewall of the chamber body 130, on which the first mainexhaust pump 160 is located, and near the first edge 304 of theprocessing volume 139 between the gas inlet 131 and the gas outlet 134in the X direction (shown in FIG. 1B). The side port 122, the gas inlet131, and the gas outlet 134 may be disposed at substantially the samelevel in the Z direction. The side port 122 is in fluid communicationwith a side exhaust pump 300 (shown in FIG. 1B).

The gas source 152 may comprise one or more gas sources, for example afirst gas source 153, and a second gas source 154, each of whichprovides a processing gas into an injection cartridge 149. In someembodiments, the first gas source 153 is a remote plasma source (RPS)that produces oxygen and hydrogen radicals. For a RadOx® process thatheats the substrate 101 with lamps and injects hydrogen and oxygenradicals into the processing volume 139, a gas injector 147 in fluidcommunication with the gas inlet 131 and the gas source 152 may beconnected to the base ring 140. A flow adjusting device 146 may beplaced between the gas source 152 and the gas injector 147 to control aflow rate of a gas flow 148. It is believed that the introduction ofhydrogen radicals improve the reaction rate along the edge of thesubstrate 101, while the substrate is rotated, during the performance ofan oxidation process, leading to an oxide layer having improvedthickness uniformity. The gas flow 148 may include 5 to 80 percenthydrogen gas by volume and 20 to 95 percent oxygen gas by volume andhave a flow rate ranging from about 1 slm to about 50 slm. In someembodiments, the gas mixture also has a concentration of argon in therange of about 5% to about 80%, for example, in the range of about 10%to about 50%. For a substrate with a 300 mm diameter, the flow rateranges from about 0.007 slm/cm² to about 0.035 slm/cm². The composition,pressure, and the flow rate of the gas flow 148 affects in thicknessuniformity of an oxide layer formed on the substrate 101.

Gas flows through from the gas source 152 optionally through theinjection cartridge 149, the gas injector 147, and the gas inlet 131into the processing volume 139. In some embodiments, the injectioncartridge 149 has an elongated channel 150 and an inlet (also referredto as an injector inlet) 143 formed therein. Injecting holes 151 aredistributed along the elongated channel 150 and are configured to injecta main gas flow 145 towards the processing volume 139 in a directionthat is at an angle to the X direction. In some embodiments of anoxidation process, the main gas flow 145 may include 5 to 80 percenthydrogen gas by volume and 20 to 95 percent oxygen gas by volume, andhave a flow rate ranging from about 1 standard liters per minute (slm)to about 50 slm while the chamber is maintained at a pressure of about 1Torr to about 19 Torr, such as between about 5 Torr to about 15 Torr andthe substrate is heated to a temperature of between about 450° C. toabout 1100° C. In some embodiments, the gas mixture also has aconcentration of argon in the range of about 5% to about 80%, forexample, in the range of about 10% to about 50%. The flow rate is basedon the substrate 101 having a 300 mm diameter, which leads to a flowrate ranging from about 0.011 slm/cm² to about 0.071 slm/cm².

The main gas flow 145 is directed from the gas flow 148 and optionallyalso from the injecting holes 151 towards the gas outlet 134 in the Xdirection. The main gas flow 145 flows into the exhaust volume 125 andis exhausted by one or both of the first and second main exhaust pumps160, 136. It is believed geometry of a processing chamber 100 (such as alocation, a shape, a direction of the exhaust volume 125), the size andposition of the openings 160A, 136A of the first and second main exhaustpumps 160, 136, and pumping speeds achieved by the first and second mainexhaust pumps 160, 136 can be used to affect the gas flow pattern, andthus flow uniformity in the processing volume 139. However, in somealternate embodiments, the exhaust volume 125 of the exhaust assembly124 extends along the direction of the main gas flow 145 such that thegeometry influence of the processing volume 139 on the main gas flow 145is reduced (e.g., located far enough from the gas inlet 131).

The first and second main exhaust pumps 160, 136 may be also used tocontrol the pressure of the processing volume 139. In one someembodiments, the pressure inside the processing volume 139 is maintainedat about 0.5 Torr to about 19 Torr, such as between about 5 Torr toabout 15 Torr. In some embodiments, the processes performed in theprocessing volume 139 operate within the viscous flow regime range. Inthis case, the first and second main exhaust pumps 160, 136 draw avolume of gas to their respective openings 160A, 136A of the first andsecond main exhaust pumps 160, 136, push the volume of gas through thepump mechanism, and expel the volume of gas to the pump inlets atatmospheric pressure. As a result, as discussed above, a gradient in thegas concentration (i.e., the gas concentration is lower near the pumpinlets and higher away from the pump inlets) is created, causing the gasinside the processing volume 139 to flow towards the pump inlets.

In one example embodiment shown in FIG. 1B, the gas injector 147 is anasymmetric structure with an opening which directs the majority of themain gas flow 145 from the gas inlet 131 towards the second edge 302 ofthe processing volume 139. Thus, the gas exposure of the substrate 101is increased at or near the second edge 302 of the processing volume139. In some embodiments, the main gas flow 145 is exhausted by thefirst and second main exhaust pumps 160, 136 on the either sides of thechamber body 130. In some embodiments, the main gas flow 145 that isdirected towards the second edge 302 of the processing volume 139 isredirected towards the first edge 304 of the processing volume 139 byuse of the side exhaust pump 300. The side exhaust pump 300 may create agradient in the gas concentration (i.e., the gas concentration is lowernear a pump inlet of the side exhaust pump 300 and higher away from thepump inlet of the side exhaust pump 300), causing the gas inside theprocessing volume 139 to flow towards the pump inlet of the side exhaustpump 300.

In some embodiments, the main gas flow 145 that is redirected towardsthe first edge 304 of the processing volume 139 is exhausted by the sideexhaust pump 300 and the first main exhaust pump 160 while the secondmain exhaust pump 136 is turned off. In some embodiments, the ratio ofexhaust flow rates of the side exhaust pump 300 to the first mainexhaust pump 160 is between 0.5:1 and 1:0.5. In other embodiments, theside exhaust pump 300, and the first and second main exhaust pumps 160and 136 are turned on. Thus, in some embodiments, the ratio of exhaustflow rates of the side exhaust pump 300 to the first main exhaust pump160 plus the second main exhaust pump 136 is between 0.5:1 and 1:0.5.

In some embodiments, the substrate 101 is rotatable in a counterclockwise direction 197, as the gas is directed towards an edge of thesubstrate 101, thus causing gas to flow over the substrate 101 resultingin more uniform growth across the substrate 101. The rotation of thesubstrate 101, in an opposing direction to the gas flow, may be used toredirect the main gas flow 145 towards the first edge 304 of theprocessing volume 139 while the gas injector 147 directs the main gasflow 145 towards the second edge 302 of the processing volume 139. Avelocity and a flow pattern of the main gas flow 145 in the processingvolume 139 may be adjusted through a rotation speed of the substrate 101and a tilted angle (referred to as a cone angle θ below) of a gasinjection channel of the gas injector 147 such that non-uniformities inthe main gas flow 145 over the substrate 101 are reduced. In someembodiments, the rotation speed of the substrate ranges between about 5and 300 rpm, and the cone angle θ may be between 10° and 35°. As aresult, the thickness profile at the edges of the substrate is improved.In some embodiments, the substrate 101 is rotatable in a clockwisedirection opposite to the counter clockwise direction 197 to furtherincrease gas velocity along the edge in order to achieve differentlydesired thickness profile.

When the main gas flow 145 (either gas or gas of radicals) is directedin a direction towards the edge of the substrate 101 near the secondedge 302 of the processing volume 139 (or the edge of the substratesupporting surface of the substrate support 138), while the substrate isrotated, the gas or gas of radicals significantly promote the reactionrate along the edge of the substrate 101 near the second edge 302 of theprocessing volume 139 versus at or near the center 308 of the substrate101. Directing gas towards the edge of the substrate 101 near the secondedge 302 of the processing volume 139 through an asymmetric gasinjection channel 249 (shown in FIG. 3A), with or without the sideexhaust pump 300, leads to an oxide layer having improved thicknessuniformity throughout the substrate 101 over directing gas towards thecenter 308 of the substrate 101. In one example of an oxidation process,the main gas flow 145 may include 5 to 80 percent hydrogen gas by volumeand 20 to 95 percent oxygen gas by volume, optionally a concentration ofargon in the range of about 5% to about 80%, a flow rate ranging fromabout 1 standard liter per minute (slm) to about 50 slm while thechamber is maintained at a pressure of about 0.5 Torr to about 19 Torr,and the substrate is heated to a temperature of between about 450° C. toabout 1100° C., and rotated in a counter clockwise direction at a speedbetween about 10 rpm and 300 rpm.

FIGS. 2A and 2B show numerical simulations of oxygen radicalconcentration over the substrate 101 with a 300 mm diameter as functionsof a position along a line in the Y direction intersecting the center308 of the substrate 101. The position indicated as “0” corresponds tothe center 308 of the substrate 101. In FIG. 2A, the side exhaust pump300 is turned off, and the first and second main exhaust pumps 160, 136are turned on. In FIG. 2B, the side exhaust pump 300 and the first mainexhaust pump 160 are turned on. In FIGS. 2A and 2B, the cone angles θare assumed to be 15° in the numerical simulations indicated by (a) and25° in the numerical simulations indicated by (b). In FIG. 2A, theoxygen radical concentration is reduced at the center 308 of thesubstrate 101 (i.e., the position indicated as “0”) for the cone angle θof 15° and 25°, respectively, and spreads towards the edges of thesubstrate 101 (i.e., the positions indicated as “150” and “−150”). InFIG. 2B, the oxygen radical concentration is reduced at the center 308of the substrate 101 (i.e., the position indicated as “0”) for the coneangle θ of 15° and 25°, respectively, and spreads towards the edges ofthe substrates 101 (i.e., the positions indicated as “150” and “−150”).

FIG. 3A is a schematic cross-sectional top view of the gas injector 147according to one embodiment. The gas injector 147 may be made of anysuitable material such as quartz, ceramic, aluminum, stainless steel,steel, or the like.

The gas injector 147 has a body 230 in which a gas injection channel 249and an opening 246 are formed. In some embodiments, the opening 246 isrectangular.

In some embodiments, the body 230 is parallelepiped. The body 230 has afirst side 232 opposite a second side 234. In some embodiments, thefirst side 232 and the second side 234 are parallel to the X axis andhave substantially the same length. The body 230 has a third side 224, afourth side 222, a fifth side 226, and a sixth side 282, as shown inFIG. 3B.

The gas injection channel 249 may have any desired shape incross-section, such as rectangular (shown in FIG. 3B), square, round,polygonal, hexagonal, trapezoidal, or any other suitable shape. The gasinjector 147 is adapted to direct the majority of the main gas flow 145to the second edge 302 of the processing volume 139. The gas injectionchannel 249 includes two interior surfaces 279, 280 (FIG. 3A). In someembodiments, the interior surface 279 extends along a direction 306 thatis substantially tangential to the edge of the substrate supportingsurface of the substrate support 138 near the second edge 302 of theprocessing volume 139. The interior surface 280 of the gas injectionchannel 249 is tilted from an axis line 210 by a cone angle θ towardsthe interior surface 279. The axis line 210 extends through the opening246 and is parallel to the X direction and perpendicular to the fifthside 226 (shown in FIG. 3B). The interior surfaces 279, 280 are alongdirections that are tilted from the axis line 210 towards the secondedge 302 and projections of these surfaces, which are all parallel tothe X-Y plane, are configured to not intersect the center 308 of thesubstrate 101. The cone angle θ may be between 5° to 45°. Interiorsurfaces 279, 280 extend from the opening 246 to the sixth side 282(shown in FIG. 3B). The sixth side 282 is curved and adjacent to thesubstrate 101 and on the opposite side of the opening 246.

In some embodiments, the opening 246 has a circular inlet 216 (as shownin FIG. 3B). The circular inlet 216 leads to an expanded interior space214 (FIG. 3A) that is in fluid communication with the gas injectionchannel 249. In some embodiments, the expanded interior space 214 has arectangular cross-sectional shape in the Y-Z plane.

FIGS. 3B and 3C are three-dimensional schematic views of the gasinjector 147. The gas injector 147 functions to direct majority of gasor gas of radicals found in the main gas flow 145 towards the secondedge 302 of the processing volume 139.

The gas injector 147 includes sides 226, 232, 234, 282, 224, and 222.The first side 232 is opposite the second side 234. In some embodiments,the first side 232 and the second side 234 are parallel to the X axisand have substantially the same length. A first curved surface 236 isdisposed between the first side 232 and the third side 224. The thirdside 224 is disposed orthogonally to the first side 232. A second curvedsurface 240 is disposed between the second side 234 and the third side224. A third curved surface 238 is disposed between the first side 232and a fourth side 222. The fourth side 222 is orthogonal to the firstside 232. A fourth curved surface 228 is disposed between the secondside 234 and the fourth side 222. The third side 224 is opposite thefourth side 222. A fifth side 226 is opposite a sixth side 282. In someembodiments, the sixth side 282 is curved. In one example, the radius ofcurvature of the sixth side 282 may be between about 160 mm to about 230mm. In another example, the radius of curvature of the sixth side 282may be between about 10 mm to about 80 mm larger than the radius of asubstrate that is to be processed in the processing volume 139. The gasinjection channel 249 is disposed on the sixth side 282 facing thesubstrate 101. The first side 232 and the second side 234 may besubstantially perpendicular to the fourth side 222 allowing for a morecohesive seal within the processing chamber 100. When the sixth side 282is curved such that the curvature contours the curvature of thesubstrate 101, turbulent gas flow is reduced in the gas flow towards thesubstrate 101, leading to uniformity in the gas flow.

FIG. 4 illustrates a schematic cross-sectional top view of the gasinjector 147 according to another embodiment. As shown, the gas injector147 includes a body 230, in which a gas injection channel 249 is formed.The gas injection channel 249 has two interior surfaces 279, 280, and aplurality of linear rudders 220. Although only two linear rudders 220are shown in the embodiment illustrated in FIG. 4, it is to beunderstood that any number of linear rudders 220 can be included in thegas injector 147. The body 203 and the linear rudders 220 can be made ofquartz or any other material unreactive to the reactant gas. The gasinjector 147 is divided into a first portion 231 and a second portion229 by a dividing line 215, wherein the dividing line 215 is parallel tothe Y-direction. The plurality of linear rudders 220 are disposed in thefirst portion 231. The first portion 231 and second portion 229 can betwo separate pieces that combine to make the gas injector 147, or thefirst portion 231 and the second portion 229 can be made of the samepiece. The gas injector 147 is coupled to the inlet 143, and the inlet143 delivers the reaction gas to the gas injector 147. The gas injector147 is configured to deliver the reaction gas to the substrate 101.

The gas injector 147 is divided into a top portion 235 and a bottomportion 233 by the axis line 210, wherein the axis line 210 is parallelto the X-direction. The linear rudders 220 are disposed and angled insuch a way that the reaction gas flows mostly or completely through thetop portion 235 of the gas injector 147, according to one embodiment. Ifthe reactant gas is allowed to flow through the bottom portion 233 ofthe gas injector 147, a large portion of the reaction gas misses themajority of the substrate area and remains unreacted or drawn into theside port 122 and then the side exhaust pump 300, wasting the reactantgas and resulting in uneven film growth on the portion of the substratedisposed over the right extent of the processing volume 139 (i.e., nearthe first edge 304). In addition, the gas injector 147 without ruddersexhibit jet stream-like flow, where the main gas flow 145 isconcentrated in one narrow stream. The gas injector 147 with rudders 220disclosed herein allows for main gas flow 145 to spread in a much widerarea, while still being focused on the left extent of the processingvolume 139 (i.e., near the second edge 302).

The main gas flow 145 through the top portion 235 of the gas injector147 allows for film growth mostly or entirely on the portion of thesubstrate 101 in the left extent of the processing volume 139 (i.e.,near the second edge 302). In addition, the increased circulation of thereactant gas due to the linear rudders 220 increases the reaction rateof the reaction gas with the substrate 101, leading to faster filmgrowth. The linear rudders 220 are disposed such that the integratedvelocity of the reactant gas over the left extent of the processingvolume 139 near the second edge 302 is as high as possible, while theintegrated velocity still being as uniform as possible in the leftextent the processing volume 139 near the second edge 302. The linearrudders 220 allow for a higher velocity of the main gas flow 145 thanother rudder shapes, such as wedges.

The plurality of linear rudders 220 can be disposed in any arrangementwithin the first portion 231 of the gas injector 147. The plurality oflinear rudders 220 have an angle α with respect to the axis line 210towards the second edge 302 of the processing volume 139. Each of thelinear rudders 220 can have the same angle α or a different angle,according to some embodiments. The angle α varies from about 5° to about85°, such as from about 25° to about 55°, or from about 35° to about45°, according to some embodiments. An end 220E of at least one of theplurality of linear rudders 220 is separated from the bottom surface 202by a distance of about 15 mm to about 60 mm, according to oneembodiment. An end 220E of at least one of the plurality of linearrudders 220 are separated from the dividing line 215 by a distance ofabout 35 mm to about 45 mm, according to one embodiment. The linearrudders in the plurality of linear rudders 220 have a length from about25 mm to about 75 mm, according to one embodiment. The plurality oflinear rudders 220 are disposed such that a main gas flow 145 of thereactant gas out of the gas injector 147 has a Reynolds number (Re) ofabout 100 or less, and the main gas flow 145 is laminar, according toone embodiment.

In some embodiments, during the delivery of the reactant gas to asurface of the substrate 101, the substrate 101 can be heated from atemperature of about 23° C. to about 1200° C. The reactant gas can bedelivered such that the reactant gas grows film on the portion of thesubstrate 101 in the left extent of the processing volume 139 near thesecond edge 302. About 60% to about 90% or more of the volume of thefilm is disposed in the left extent of the processing volume 139 nearthe second edge 302.

Even though a thermal processing chamber is discussed in thisapplication, implementations of the present disclosure may be used inany processing chamber where uniform gas flow is desired.

Benefits of the present disclosure include the use of an asymmetric gasinjector in a processing chamber to direct gas towards the edge of thesubstrate to control growth uniformity throughout the substrate. Theasymmetric gas injector points to a gas flow towards an edge of theprocessing volume. The gas flow can be further redirected to the otheredge of the processing volume by a side pump. Particularly, it has beenobserved that directing gas through an asymmetric gas channel willsignificantly increase the reaction at or near the edge of the substratein a RadOx® process, thereby leading to improved thickness uniformityalong the edge of the substrate as well as an improved overall thicknessuniformity of the substrate.

While the foregoing is directed to implementations of the presentdisclosure, other and further implementations of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. A gas injector for processing a substrate,comprising: a body having an inlet connectable to a gas source that isconfigured to provide a gas flow in a first direction into the inletwhen processing a substrate on a substrate support disposed within aprocessing volume of a processing chamber, wherein the substrate supporthas a first edge and a second edge opposite the first edge in adirection orthogonal to the first direction; and a gas injection channelformed in the body, wherein: the gas injection channel is in fluidcommunication with the inlet; the gas injection channel is configured todeliver the gas flow to a processing chamber inlet of the processingchamber; the gas injection channel has a first interior surface that isparallel to a second direction and a second interior surface that isparallel to a third direction; the first, second, and third directionsare parallel to a first plane; the second and third directions do notintersect a center of the substrate, and are at an angle to the firstdirection towards the second edge of the substrate support; the seconddirection is tilted from the first direction by between 15° to 35°towards the second edge of the substrate support; and the thirddirection is substantially tangential to the second edge of thesubstrate support.
 2. The gas injector according to claim 1, furthercomprising: a first side parallel to the first direction; a second sideparallel to the first direction and opposite the first side in a fourthdirection that is orthogonal to the first direction, the second sidehaving substantially the same length as the first side; a third sideparallel to the fourth direction; a first curved surface extendingbetween the first side and the third side; a second curved surfaceextending between the third side and the second side; a fourth sideparallel to the fourth direction and opposite the third side in a fifthdirection that is orthogonal to the first direction and the fourthdirection; a third curved surface extending between the first side andthe fourth side; a fourth curved surface extending between the fourthside and the second side; a fifth side parallel to the fourth direction;and a sixth side parallel to the fourth direction and opposite the fifthside in the first direction, wherein the inlet is disposed on the fifthside and the gas injection channel is disposed on the sixth side.
 3. Thegas injector according to claim 1, further comprising a plurality oflinear rudders disposed within the gas injection channel.
 4. The gasinjector according to claim 3, wherein each linear rudder of theplurality of linear rudders is tilted from the first direction bybetween 25° to 55° towards the second edge of the substrate support. 5.The gas injector according to claim 3, wherein an end of at least onelinear rudder of the plurality of linear rudders is separated from aninterior surface of the gas injection channel by a distance of between15 mm and 60 mm.
 6. An apparatus for processing a substrate, comprising:a chamber body having a chamber gas inlet, a chamber gas outlet, and aprocessing volume between the chamber gas inlet and the chamber gasoutlet in a first direction; a substrate support disposed within theprocessing volume; a gas injector having an injector inlet and a gasinjection channel, wherein: the injector inlet is connectable to a gassource that is configured to provide a gas flow in the first directioninto the injector inlet when processing a substrate on the substratesupport; the gas injection channel is in fluid communication with theinjector inlet; and the gas injection channel is configured to deliverthe gas flow to the chamber gas inlet; an exhaust assembly coupled tothe chamber gas outlet; and a side exhaust pump coupled to theprocessing volume via a side port of the chamber body, wherein: the sideport is disposed near a first edge of the substrate support; the gasinjection channel has a first interior surface that is parallel to asecond direction and a second interior surface that is parallel to athird direction; the first, second, and third directions are parallel toa first plane; and the second and third directions do not intersect acenter of the substrate, and are at an angle to the first directiontowards a second edge of the substrate support opposite the first edgein a fourth direction that is orthogonal to the first direction.
 7. Theapparatus according to claim 6, wherein the substrate support isrotatable around the center of the substrate.
 8. The apparatus accordingto claim 6, wherein: the second direction is tilted from the firstdirection by between 15° to 35° towards the second edge of the substratesupport; and the third direction is substantially tangential to thesecond edge of the substrate support.
 9. The apparatus according toclaim 6, wherein the exhaust assembly comprises a first main exhaustpump.
 10. The apparatus according to claim 6, wherein the exhaustassembly comprises a first main exhaust pump and a second main exhaustpump.
 11. The apparatus according to claim 6, wherein the gas injectorfurther comprises: a first side parallel to the first direction; asecond side parallel to the first direction and opposite the first sidein the fourth direction that is orthogonal to the first direction, thesecond side having substantially the same length as the first side; athird side parallel to the fourth direction; a first curved surfaceextending between the first side and the third side; a second curvedsurface extending between the third side and the second side; a fourthside parallel to the fourth direction and opposite the third side in afifth direction that is orthogonal to the first direction and the fourthdirection; a third curved surface extending between the first side andthe fourth side; a fourth curved surface extending between the fourthside and the second side; a fifth side parallel to the fourth direction;and a sixth side parallel to the fourth direction and opposite the fifthside in the first direction, wherein the injector inlet is disposed onthe fifth side and the gas injection channel is disposed on the sixthside.
 12. The apparatus according to claim 6, wherein the gas injectorfurther comprises a plurality of linear rudders disposed within the gasinjection channel.
 13. The apparatus according to claim 12, wherein eachlinear rudder of the plurality of linear rudders is tilted from thefirst direction by between 25° to 55° towards the second edge of thesubstrate support.
 14. The apparatus according to claim 12, wherein anend of at least one linear rudder of the plurality of linear rudders isseparated from an interior surface of the gas injection channel by adistance of between 15 mm and 60 mm.
 15. A gas injector for processing asubstrate, comprising: a body having an inlet connectable to a gassource that is configured to provide a gas flow in a first directioninto the inlet when processing a substrate on a substrate supportdisposed within a processing volume of a processing chamber, wherein thesubstrate support has a first edge and a second edge opposite the firstedge in a direction orthogonal to the first direction; and a gasinjection channel formed in the body, wherein: the gas injection channelis in fluid communication with the inlet; the gas injection channel isconfigured to deliver the gas flow to a processing chamber inlet of theprocessing chamber; the gas injection channel has a first interiorsurface that is parallel to a second direction and a second interiorsurface that is parallel to a third direction; the first, second, andthird directions are parallel to a first plane; the second and thirddirections do not intersect a center of the substrate, and are at anangle to the first direction towards the second edge of the substratesupport; and the second and third directions are not the same.
 16. A gasinjector for processing a substrate, comprising: a body having an inletconnectable to a gas source that is configured to provide a gas flow ina first direction into the inlet when processing a substrate on asubstrate support disposed within a processing volume of a processingchamber, wherein the substrate support has a first edge and a secondedge opposite the first edge in a direction orthogonal to the firstdirection; and a gas injection channel formed in the body, wherein: thegas injection channel is in fluid communication with the inlet; the gasinjection channel is configured to deliver the gas flow to a processingchamber inlet of the processing chamber; the gas injection channel has afirst interior surface that is parallel to a second direction and asecond interior surface that is parallel to a third direction; thefirst, second, and third directions are parallel to a first plane; thesecond and third directions do not intersect a center of the substrate,and are at an angle to the first direction towards the second edge ofthe substrate support; and the second and third directions are notparallel.
 17. A method for processing a substrate, comprising: injectinga gas flow in a first direction from a gas source into a gas injectorwhen processing a substrate on a substrate support disposed within aprocessing volume of a processing chamber, the substrate support havinga first edge and a second edge opposite the first edge in a directionorthogonal to the first direction, wherein the processing chamber has achamber gas inlet and a chamber gas outlet, and the substrate support isdisposed between the chamber gas inlet and the chamber gas outlet in thefirst direction; and injecting the gas flow from the gas injector intothe processing chamber, wherein: the gas flow from the gas injector isdirected between a second direction and a third direction; and thesecond and third directions do not intersect a center of a substratedisposed on the substrate support and are at an angle to the firstdirection towards the second edge of the substrate support; and whereinthe gas injector comprises: a body having an inlet connectable to thegas source that is configured to provide the gas flow in the firstdirection into the inlet when processing the substrate; and a gasinjection channel formed in the body, wherein: the gas injection channelis in fluid communication with the inlet; the gas injection channel isconfigured to deliver the gas flow to a processing chamber inlet of theprocessing chamber; the gas injection channel has a first interiorsurface that is parallel to the second direction and a second interiorsurface that is parallel to the third direction; the first, second, andthird directions are parallel to a first plane; the second direction istilted from the first direction by between 15° to 35° towards the secondedge of the substrate support; and the third direction is substantiallytangential to the second edge of the substrate support.
 18. The methodaccording to claim 17, further comprising rotating the substrate supportaround the center of the substrate.
 19. The method according to claim17, further comprising exhausting the gas flow from the chamber gasoutlet by a first main exhaust pump disposed on a first side of theprocessing chamber and a second main exhaust pump disposed on a secondside of the processing chamber, the second side being opposite the firstside in a fourth direction that is orthogonal to the first direction.20. The method according to claim 17, further comprising exhausting thegas flow from the chamber gas outlet by a first main exhaust pumpdisposed on a first side of the processing chamber and from theprocessing volume by a side exhaust pump disposed on the first side ofthe processing chamber near the first edge of the substrate support.